unbound/util/timehist.h

   1 /*
   2  * util/timehist.h - make histogram of time values.
   3  *
   4  * Copyright (c) 2007, NLnet Labs. All rights reserved.
   5  *
   6  * This software is open source.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * Redistributions of source code must retain the above copyright notice,
  13  * this list of conditions and the following disclaimer.
  14  *
  15  * Redistributions in binary form must reproduce the above copyright notice,
  16  * this list of conditions and the following disclaimer in the documentation
  17  * and/or other materials provided with the distribution.
  18  *
  19  * Neither the name of the NLNET LABS nor the names of its contributors may
  20  * be used to endorse or promote products derived from this software without
  21  * specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  24  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  25  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  26  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  27  * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  28  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
  29  * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  30  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  31  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  32  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  33  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  34  */
  35
  36 /**
  37  * \file
  38  *
  39  * This file contains functions to make a histogram of time values.
  40  */
  41
  42 #ifndef UTIL_TIMEHIST_H
  43 #define UTIL_TIMEHIST_H
  44
  45 /** Number of buckets in a histogram */
  46 #define NUM_BUCKETS_HIST 40
  47
  48 /**
  49  * Bucket of time history information
  50  */
  51 struct th_buck {
  52         /** lower bound */
  53         struct timeval lower;
  54         /** upper bound */
  55         struct timeval upper;
  56         /** number of items */
  57         size_t count;
  58 };
  59
  60 /**
  61  * Keep histogram of time values.
  62  */
  63 struct timehist {
  64         /** number of buckets */
  65         size_t num;
  66         /** bucket array */
  67         struct th_buck* buckets;
  68 };
  69
  70 /**
  71  * Setup a histogram, default
  72  * @return histogram or NULL on malloc failure.
  73  */
  74 struct timehist* timehist_setup(void);
  75
  76 /**
  77  * Delete histogram
  78  * @param hist: to delete
  79  */
  80 void timehist_delete(struct timehist* hist);
  81
  82 /**
  83  * Clear histogram
  84  * @param hist: to clear all data from
  85  */
  86 void timehist_clear(struct timehist* hist);
  87
  88 /**
  89  * Add time value to histogram.
  90  * @param hist: histogram
  91  * @param tv: time value
  92  */
  93 void timehist_insert(struct timehist* hist, struct timeval* tv);
  94
  95 /**
  96  * Find time value for given quartile, such as 0.25, 0.50, 0.75.
  97  * The looks up the value for the i-th element in the sorted list of time
  98  * values, as approximated using the histogram.
  99  * @param hist: histogram. Interpolated information is used from it.
 100  * @param q: quartile, 0.50 results in the median. Must be >0 and <1.
 101  * @return: the time in seconds for that percentage.
 102  */
 103 double timehist_quartile(struct timehist* hist, double q);
 104
 105 /**
 106  * Printout histogram
 107  * @param hist: histogram
 108  */
 109 void timehist_print(struct timehist* hist);
 110
 111 /**
 112  * Log histogram, print it to the logfile.
 113  * @param hist: histogram
 114  * @param name: the name of the value column
 115  */
 116 void timehist_log(struct timehist* hist, const char* name);
 117
 118 /**
 119  * Export histogram to an array.
 120  * @param hist: histogram
 121  * @param array: the array to export to.
 122  * @param sz: number of items in array.
 123  */
 124 void timehist_export(struct timehist* hist, size_t* array, size_t sz);
 125
 126 /**
 127  * Import histogram from an array.
 128  * @param hist: histogram
 129  * @param array: the array to import from.
 130  * @param sz: number of items in array.
 131  */
 132 void timehist_import(struct timehist* hist, size_t* array, size_t sz);
 133
 134 #endif /* UTIL_TIMEHIST_H */